Merge pull request #1 from takikawa/master

Revise README
command line arguments and environment variable for config file.

Fixes #2
change order of raco link
server accepts only localhost connections for security reasons
finding modifiers also when shifted (index=1)
updating simple.rkt
reorganizing files

No semantic change
add author/license headers
Key/mouse bindings can now use string-like format.
add add-bindings + update config files
add file
reorganize file.
move window to workspace
fix bugs
added root-keymap
remove comments
some cleanup; added move to wrokspaces; restore input focus to mapped window
user switch between workspaces + move windows
formatting
fix bug: trying to move a root window between workspaces
workaround for click-to-focus